The environmental impact of the construction industry is a concern and research in the development of eco-friendly construction materials should be a high priority. New construction materials or even just improving conventional construction materials is imperative for a more sustainable built environment. The objective is to both develop new construction materials but also reduce the environmental impact of currently used construction materials. The activities are within the field of alternative masonry units, including material development, structural testing, determining suitable specifications and lasting implementation on a large scale. Work is also done on researching more eco-friendly cement-based binders and natural fibres in a cement-based matrix. Alkali activated materials are also investigated as an alternative for conventional concrete.
Fibre reinforced concrete (FRC) is becoming a more popular construction material due to the positive contribution it makes to concrete. Fibres can be divided into two general geometric categories, namely micro fibres (length typically less than 15 mm) and macro fibres (lengths at least 30 mm). Fibres can also be manufactured from different materials, most common being steel, polypropylene, glass and PVA. Natural fibres can also be used. The greatest advantage of adding fibres to concrete is the improved post cracking behaviour of concrete in tension and flexure. Micro fibres are often used for the reduction of the risk of plastic shrinkage cracking, or increasing the ductility of concrete in the case of Strain Hardening Cement-based Composite (SHCC). UCM has focused on a large number of aspects of FRC, but most recently the focus has been on the use of macro synthetic fibres and the creep of cracked FRC.
The characteristics of fresh and young concrete have a significant influence on both the mechanical and durability properties of hardened concrete. Fresh concrete refers to concrete that has just been cast while young concrete refers to concrete only a few days old and the characteristic to investigate include: deformation, defects, rheology as well as mix design. Due to the wide scope of this field, the current focus is on the prevention of early age cracking of concrete, since the presence of these early cracks can have a major detrimental effect on the service life of any concrete structure. The research activities include research on plastic settlement cracking, plastic shrinkage cracking and thermal cracking of fresh and young concrete and are aimed at providing guidelines as well as the understanding needed for the prevention of early age cracking of fresh and young concrete.
High Strength Concrete (HSC) is a type of High Performance Concrete (HPC), which has a compressive strength between 60 MPa and 120 MPa. The current structural design code used in South Africa, SANS 10100, does not allow for the design of concrete members using strengths of more than 50 MPa. The Euro Code, EN 1992-1, however, does allow for concrete up to 105 MPa cube strength. With the revision of SANS 10100 the local South African industry will be able to specify concrete up to 105 MPa. However, little is known about HSC using local materials. This research aims to investigate the properties of HSC using local materials and also develop mix design methods using these materials. Further focus is placed on the autogenous shrinkage, which is an important property of HPC to take note of, and ways to mitigate this time-dependent deformation.